The art is aware of numerous ways of accommodating the expansion and contraction of conduits such as pipes by providing movable means at the points where they are supported by either hangers or brackets. One conventional technique is to utilize pin rollers of relatively narrow diameter of various forms which underlie the conduit and rotate on a bushing mounted on an axle, thereby turning as the conduit moves during expansion and contraction. These rollers can be also provided with trunnions or bearings which are also supported on brackets or other means provided as the supports for the conduits. Examples of this type of tube support are shown in U.S. Pat. No. 3,026,858, U.S. Pat. No. 1,645,762, U.S. Pat. No. 425,856 and U.S. Pat. No. 2,893,669.
Another means for supporting a pipe whereby expansion of the pipe upon heating and contraction upon cooling is provided as shown in U.S. Pat. No. 2,738,151. This describes a rocker base member in which the rocker base rests on, but is unattached to a support member and has an upper plate support member which is rigidly attached to the pipe which is to be permitted to expand and contract. The present invention is an improvement of U.S. Pat. No. 2,738,151.
The disadvantage of the arrangement of the '151 patent is multi-fold. One problem is that periodically along the length of the pipe rigid support members must be welded directly to the pipe. This requires the pipe itself to be structurally stronger than conventional design. It also requires an extraordinary weld that must tolerate a variety of multidirectional stresses and do not distort or break the pipe itself.
And most importantly, if the rocker described in '151 rested on top of an elevated horizontal support, it would inevitably transfer its load point in a twisting moving relationship so that a support designed to carry a given load at a given point would be subjected to undue variable stresses and twistings, which can lead to breaking or deformation. It would be difficult, if not impossible, to design any support member that could withstand such an intense variation in load stresses.